The present invention relates to data transfer systems and has been developed with particular attention paid to the possible application to cycles, such as competition bicycles. In any case, the reference to this possible application, and in particular the reference to the application to racing bicycles, must not be interpreted as limiting the possible field of application of the invention.
Over the last few years there has developed, in the cycle sector, the tendency to associate to cycles sensors of various nature so as to be able to acquire information of various kinds regarding the use/behaviour of the means, for instance, in order to be able to intervene through actuators to modifyxe2x80x94according to certain criteria, acting both in an automatic way and according to specific commands issued by the user the conditions of use/behaviour of the means, in particular as regards its set.
This tendency is expressed, in particular, in the direction of a continuous increase in the quantity of data picked up and processed, which results in the need to have available increasingly more sophisticated and articulated systems, these being systems which, since they have to be mounted on board the cycle, must not adversely affect the performance of the latter, in particular in terms of weight, overall dimensions, and consumption of electrical energy.
The purpose of the present invention is to meet the ever-greater needs felt in the sector, overcoming the drawbacks outlined above.
According to the present invention, this purpose is achieved thanks to a system having the characteristics specifically called for in the claims which follow.
In particular, the invention makes possible an interfacing solution, such as to enable a limitation of the amount of connections linked to the transfer of data in the context of the system.
In this way it is possible to reduce the connections, eliminating at least part of them.
In particular, the solution according to the invention proves especially advantageous for applications of a wireless type, i.e., via data transfer on a carrier (or possibly optical means). This enables the use, for instance of networks of the type currently known as Wireless Local Area Networks (WLANs), the foregoing with the possibility of increasing the number of interfaceable sensors and with a reduction in data-transfer times.
In particular, the solution according to the invention exploits the randomness with which a fair number of the events involving the sensors occur in order to achieve transfer of the information in a predictable and reliable way without prejudice to an important aspect, such as that of power absorption, and hence that of operating autonomy of the system.
In the currently preferred embodiment, the invention envisages the creation of a local communication network which can be located on a bicycle. Present in this network are a main network manager and a set of peripheral modules provided with a capacity of their own for pre-processing the signal and with autonomy from the energy standpoint.
The operating criterion is of the master-slave type, with a main unit configured as master for the network that is designed to generate the synchronizing signals, to which the various modules forming part of the system, configured as slave units, refer to communicate their information.
Reserved to each module is a time slot, within which transmission can take place, and this enables, among other things, identification of the sensor and the corresponding signal even without including, in the signal transmitted by the sensor, a respective set of data identifying the sensor and/or the signal transmitted by it.
Bi-directional communication is made possible between the master unit and the peripheral modules so as to enable configuration of the network in an optimal way and improvement of reliability of communication.
Preferably, communication is not made when the event (for example, an individual pulse indicating rotation of a wheel, an individual pulse indicating pedal cadence, etc.) occurs, but rather in appropriate points in time.
Preferably envisaged is the possibility of pre-processing the information of the sensors locally and making this information available for transfer when pre-determined conditions arise.
Preferably, the transmission of the data item from the sensor only occurs when there exists an effective need to inform the processing/display unit normally associated to the system.
The aforesaid need to transmit information is usually linked to the fact that the event detected has a character of importance for the processing unit. With reference, by way of example, to a cycle, such as a bicycle, if the bicycle is stationary there is no need to occupy the communication channel (with the consequent power consumption). Likewise, if the bicycle is being pushed by hand (consequently, at a low speed, below a pre-defined limit), it is not necessary to transfer the information regarding rotation of the wheel to the processing unit.
Along the same lines, if the rider of the bicycle is not pedalling, or if the pedalling force is below a pre-set minimum limit, there does not exist the need to transmit the signals of the pedal-cadence sensor and/or of the pedalling-force sensor to the processing unit.
Preferably, the peripheral pre-processing modules are able to process the information coming from the corresponding sensors before deciding to make the said information available for communication.
In a preferred way, the aforesaid peripheral modules are of the wireless type and envisage basically:
a microcontroller for processing the information coming from the corresponding sensor and for performing the function of controlling the radio-frequency communication part;
a radio-frequency transceiver that can enable sending and receiving of data on a radio-frequency channel according to modalities and techniques coordinated by the microcontroller; and
a power-supply source, for instance a local battery, which makes it possible to achieve autonomy from the energy standpoint; preferably associated to the source is a circuit for monitoring the level of charge of the power-supply source itself.
Preferably, installation modalities of the plug-and-play type are envisaged, as well as specific functions that can pre-qualify the behaviour of the device when this is introduced into the network.
An important characteristic of the solution according to the invention is linked to power consumption: by shortening the times of occupation of the transmission channels, and in particular of the radio-frequency channel, it is possible to reduce power consumption to the minimum.
Preferably, the microcontrollers of the peripheral modules are configured (usually at a level of strategy of the corresponding firmware) in such a way as to carry out the following functions:
detection of signal (acquisition, filtering, conditioning, etc.);
processing, so as to bring the corresponding information into a format usable by the main processing and display system;
activation of algorithms for optimization of power consumption; and
implementation of algorithms for recovering information in the presence of possible errors on the communication channel (i.e., in situations in which the information does not reach destination).
The plurality of sensors that can be mounted on the cycle, the corresponding reactivity that is desirable in the control system, and the techniques of modulation designed to guarantee optimal reliability of the communication channel point towards the use of relatively high frequencies as preferential for the purposes of radio-frequency communication.
In the currently preferred embodiment of the invention, radio-frequency devices are adopted which preferably use Industrial-Scientific-Medical (ISM) frequency bands, and hence frequencies from 902 to 928 MHz and from 2400 to 2483.5 MHz, and frequency bands for Short-Range Device (SRD) applications, in particular from 433 MHz to 434.8 MHz, from 868 to 870 MHz, and from 2400 to 2483.5 MHZ. Preferably, with such devices relatively short communication times may be obtained, with a greater possibility of transmitting information of a number of sensors per unit time.